Oh wow, what a horrible situation!
I'm so sorry you're feeling so vulnerable in your own home.
Have you tried talking to the police to see if there's an increase in crime in your neighborhood? I think you can check those stats online, too, but I can't remember the name of the site.
I know some police departments will also send someone out to do a security check of your home to see where you need to make some changes, like changing locks, securing windows better, that kind of thing.
Just talking to someone in law enforcement will likely make you feel much better. Plus knowledge is power, and you're obviously feeling pretty powerless right now.